1. Field of the Invention
The present invention relates to a calendar mechanism and an analog timepiece equipped therewith, and more particularly relates to a calendar mechanism of a so-called big date form wherein the ones column and tens column of the date are indicated with separate date indicators, as a result of which it is possible to indicate the date in large characters, and to an analog timepiece equipped with the calendar mechanism.
2. Description of the Related Art
As a calendar mechanism of a big date form, a calendar mechanism is proposed which includes a first date indicator including a first date character indication portion which, being circular as a whole, indicates the ones column of the date, a circular first date indicator gear portion which, being formed on the inner periphery of the first date character indication portion, receives a torque, and a drive cam portion which, being formed on the back side of a first date character indication surface portion, defines an endless ring-shaped cam face; a drive cam lever including a driven lever portion whose one end portion abuts against the drive cam portion as a cam follower, and an operating lever portion which, being integral with the driven lever portion, includes a first fan-shaped gear portion at the leading end portion, wherein when the driven lever portion is pivoted in a condition in which the one end portion is in abutment with the cam face of the drive cam portion, the first fan-shaped gear portion of the operating lever portion is pivoted in accordance with the pivoting of the driven lever portion; and a second date indicator including a second date character indication portion which indicates the tens column of the date, and a second fan-shaped gear portion meshing with the first fan-shaped gear portion (for example, JP-A-2007-218856).
However, with the calendar mechanism proposed in JP-A-2007-218856, when the one end portion of the driven lever portion of the drive cam lever is in engagement with a specified cam surface portion (for example, a region corresponding to the dates of 01 to 09) of the drive cam portion of the first date indicator, it is indispensable that the first and second fan-shaped gear portions mesh with each other by means of their teeth in specified positions in accordance with this condition (it is indispensable that their rotation phases are caused to coincide with each other), but nevertheless, in the event that one tooth of each gear portion comes unmeshed, the first and second date indicators and drive cam lever are assembled in a condition in which this indispensable condition is not fulfilled (a noncoincidence condition), and the calendar mechanism in the noncoincidence condition causes a misalignment of the date characters of the second date indicator, thus preventing an appropriate date indication, and indicating unlikely dates such as “32nd” to “39th”.